Arching Effect Research Articles

Stress disturbance induced by twin-tunneling in sandy ground considering soil arching effect

Stress disturbance induced by twin-tunneling in sandy ground considering soil arching effect

Experience in developing a javascript component for implementing logo deformation effects when applied on product images

The development of an online store for selling goods is quite relevant in view of the possibilities of attracting new customers. The main task in promoting a store on the Internet market is to ensure competitive advantages and uniqueness of content. Visual configuration of a product is such a tool. It ensures consumer interest, the formation of a unique offer for him and provides an individual approach and loyalty. This is especially important for companies that offer the application of any logos on souvenir products. At the same time, it is important to provide the user with tools for applying various effects to the logo image when placing it on the product image. When researching and selecting tools to implement this task, the use of JavaScript for development, as well as the Canvas component for displaying images with warp effects, was justified. Using JavaScript, universal components were developed that allow applying the following deformation and distortion effects to logo images: deformation effects using the quadratic Bezier curve equation, deformation effects using the ellipse equation, deformation with an arch effect, deformation with a perspective effect.

Full Life Cycle Evaluation of Stability Pile in High Slope with Multi-Layer Weak Interlayers

High slopes with multi-layer weak interlayers are a type of special slope that tends to fail due to the unfavorable mechanical properties of interlayers. In this study, the influence of the position, length, diameter, and ratio of on-center spacing to the pile diameter on the stability of such slopes is investigated using the three-dimensional strength reduction elastoplastic finite element method. Based on a high slope with multi-layer weak interlayers, two models were created, and three states (an initial state, a state with a safety factor of 1.35, and a limit equilibrium state) were considered. The pile can improve slope stability when the it is located at the lower to lower-middle part of a high slope. The resistance effect no longer has a strengthening property if it exceeds a critical pile length (28 m and 30 m in the two models); 30 m was found to be the optimal pile length for the high slope. As the diameter increased, the safety factor increased from 1.38 (1.37) to 1.41 (1.40) in Model 1 (or in Model 2), while the maximum compressive stress, the maximum shear stress of the pile, and the maximum displacement of the pile head decreased in the two models from 20.84 (81.24) MPa to 16.15 (18.8) MPa, 11.19 (42.02) MPa to 7.77 (10.43) MPa, and 714.1 (4585.00) mm to 396.3 (1272.00) mm, respectively. The pile diameter should be >1.4 m in such cases. When stress and displacement increased, the arching effect and the pile group effect weakened, and the safety factor decreased as the ratio of on-center spacing to diameter increased. The ratio should be <3 to ensure slope ability.

Study of Asymmetric Face Failure and Limit Support Pressure During Curved Tunnels Excavation in Sandy Soils

ABSTRACTWith the continuous urban development, tunnels are increasingly designed with curved alignments to avoid existing structures and to make better use of the underground space. However, these tunnels are usually subjected to complex forces, and current research on the curved tunnels face stability remains incomplete. This paper presents a detailed face stability analysis of curved tunnels, both analytically and numerically. Initially, a series of 3‐D numerical simulations are performed to investigate the spatially asymmetric failure pattern of the soil ahead of the curved tunnel face and the stress transfer mechanism of the soil arching effect during the excavation process is explored. Subsequently, based on traditional limit equilibrium methods and the results from numerical simulations, an improved wedge‐prism model and corresponding theoretical calculation formulas for the limit support pressure are proposed. The validity of the improved model is confirmed through illustrative analyses, while sensitivity analyses are conducted on the impacts of soil internal friction angle, structural depth ratio, and tunnel curvature radius on the limit support pressure. This study can aid in the calculation of the stability of the tunnel face and the limit support pressure in curved tunnel excavation.

A novel two-layer composite geomembrane lining structure to mitigate frost damage in cold-region canals: Model test and numerical simulation

The canal is crucial for water diversion projects, but it is susceptible to frost damage. To address this, a two-layer composite geomembrane lining structure (TLCGLS) was proposed that regulates the interaction between canal lining and frozen soil. Model tests were conducted to investigate its anti-frost heave effectiveness. Considering the interaction among the lining, two-layer composite geomembranes (TLCGs), and frozen soil, a canal frost heave model with heat-water-mechanical coupling was developed. The influence of canal cross-section shapes and TLCGs arrangements on anti-frost heave performance and mechanism of TLCGLS were discussed. Results show that TLCGLS reduces uneven frost heave degree and compressive/tensile strains of the lining by 35%, 29%, and 28% respectively. During melting, it rapidly reduces frost heave, tangential deformation, and strain with minimal residual effects. TLCGLS demonstrates strong resetting ability and excellent anti-frost heave performance. It is particular suitable for arc-bottomed trapezoidal canals. However, excessive reduction in friction between TLCGs weakens arching effect of the bottom lining, increasing tensile stress and safety risks. TLCGLS with geomembrane-geotextile contact exhibits superior anti-frost heave performance, mitigating compressive stress by over 50% while meeting design requirements for tensile stress. These findings provide a theoretical basis and technical solution for mitigating frost damage in canals.

Considering the changes in unsaturated soil saturation after pipeline leakage: A modified Terzaghi model

Pipeline leakage leads to the saturation and weakening of the surrounding soil, increasing the pressure exerted by the overlying soil on underground engineering structures and posing a serious threat. Therefore, it is necessary to thoroughly understand the influence of pipeline leakage on the overlying soil pressure. Based on the saturation distribution within different diffusion ranges, an analysis model for pressure in loose soil under the influence of pipeline leakage was presented. Considering the variation in the matric suction of the unsaturated soil, the soil pressure can be modeled based on the incomplete arch effect. The influence of the relevant parameters on the overlying soil pressure was analyzed, and the accuracy and rationality of the modified model were verified using a trapdoor test. These findings indicate that the modified model can accurately estimate the soil pressure caused by a pipeline leakage. The overlying soil pressure is directly proportional to the diffusion distance, tunnel width, and slip surface inclination angle and inversely proportional to the relative deformation. The rate of change was mainly influenced by the parameters affecting the soil arching effect. The modified model presented in this study can be used to directly calculate the overlying soil pressure affected by pipeline leakage. This calculation is based on the known physical and mechanical parameters of unsaturated soil, pipeline leakage range, and relative deformation of the tunnel, thus providing a theoretical basis for the design of structures under urban pipelines.

Comparative study of failure mechanism of CFRP partially confined normal strength concrete (NSC) and UHPC cylinders under axial compression

Ultra-high performance concrete (UHPC) holds significant potential in marine structures due to its superior compressive strength and enhanced durability in comparison to normal strength concrete (NSC). Carbon fiber-reinforced polymer (CFRP) confinement has been proven to improve these properties further. However, the compressive behavior of CFRP-confined UHPC, especially for partial confinement, presents complexities arising from the intricate interaction mechanism between UHPC and wrapped CFRP strips. To address this issue, the present study conducted axial compression tests accompanied by digital image correlation (DIC) analyses. Failure modes, stress-strain behavior, hoop strain distribution, and cracking evolution of CFRP partially confined NSC/UHPC were elucidated, thereby uncovering the underlying load transfer mechanism between NSC/UHPC and wrapped CFRP strips. Research outcomes show that the enhancement in compressive strength fcc/fco (0.99 ∼ 1.43) and strain εcu/εco (1.51 ∼ 2.59) of CFRP partially confined UHPC is relatively lower than the NSC counterparts (1.28 ∼ 2.98 and 3.82 ∼ 15.14, respectively). Moreover, lower hoop strain efficiency εh,rup/εfrp can be found for CFRP partially confined UHPC compared to NSC (0.61 vs. 0.86). These phenomena were primarily attributed to the localized shear-cracking pattern and low dilation behavior of confined UHPC. Based on the experimental results, the elucidation of the underlying load transfer mechanism between UHPC/NSC and wrapped CFRP strips provides valuable insights into comprehending the compressive behavior of CFRP partially confined UHPC. Finally, the “arching effect” is found to exhibit limited effect on the ultimate condition’s prediction of partially confined UHPC according to the failure mechanism and Li et al.’s model can reliably predict the ultimate conditions among the existing models.

Practical methodology for quantifying the structural robustness of RC building structures

Several structural robustness requirements have been included in building codes over the past two decades. These mainly include measures to prevent collapse after an initial component failure by ensuring a minimum level of continuity within the structural system so that loads supported by the failed component can be redistributed to the rest of the structural system. However, there is still a general lack of consensus on how to evaluate the effectiveness of these measures. The present study proposes a practical methodology to evaluate the structural robustness of RC building structures by combining an efficient modelling strategy and suitable robustness indexes. The proposed computational modelling strategy for RC buildings accounts for relevant dynamic and nonlinear phenomena, including compressive arching, catenary action, and membrane effects. This strategy can be implemented at a reasonable computational expense in widely used commercial structural analysis software and has been validated by comparisons to selected experimental tests from the literature. The modelling strategy is then employed to compute four different robustness indexes proposed in the literature for three hypothetical building designs, allowing the indexes to be systematically compared. It was found that evaluating a system using multiple robustness indexes can provide a more holistic view of system performance compared to relying solely on a single index. Ultimately, the potential usefulness of the proposed methodology is demonstrated through two practical applications involving the estimation of component damage levels and the evaluation of different design and retrofitting solutions. Such a methodology can be useful for practising engineers to optimise the design of new buildings or to support decisions on the assessment and retrofitting of existing ones.

Application of VAR-GARCH for Modeling the Causal Relationship of Stock Prices in the Mining Sub-sector

Accurate modeling is expected to minimize risk and maximize profit in investment portfolios, one ofwhich is in stock price modeling. This research aims to model the causal relationship between stockprices using the Vector Autoregressive - Generalized Autoregressive Conditional Heteroskedasticity(VAR-GARCH) model. The VAR-GARCH model is used to overcome heteroscedasticity and modeldynamic volatility. The data used for the modeling consists of daily stock prices from July 2023 toMay 2024 for mining sub-sector companies listed on the Jakarta Islamic Index (JII), including ADMR,ADRO, and ANTM. The results showed that the VAR(1) model is stable, but this model indicates thepresence of heteroskedasticity or ARCH effects. Therefore, the VAR(1) model was combined with theGARCH model, and the results showed that the best model is VAR(1)-GARCH(1,1). The VAR(1)-GARCH(1,1) model is appropriate and meets the homoskedasticity assumptions for modeling the stockprices of the mining sub-sector in the Jakarta Islamic Index (JII). This indicates that the VAR-GARCHmodel could successfully handle the volatility of stock price data. In general, this research is in linewith previous research, i.e., the VAR-GARCH model showed a better model for capturing the volatilitypatterns in the data.

An experimental investigation on the arching effect of cohesive materials in trapdoor tests

This study conducted a series of trapdoor tests on low cohesion material at different buried depths, the failure patterns and the variations of soil pressure were investigated, and the development of the arching effect in trapdoor tests was analyzed. The results showed two failure models for soils: when the buried depth ratio was smaller than 2, two rupture surfaces developed obliquely upward from two sides of the trapdoor and merged into one triangular rupture surface; when the ratio was greater than 2, two rupture surfaces developed vertically upward and merged into one tower-shaped rupture surface. As the burial depth increased, the inner boundaries of the soil arch moved upward, and the widths of the inner and outer boundaries expanded. Furthermore, the maximum arching trajectory, obtained by connecting the maximum tangential stress points, was closer to the inner boundary and shifted towards the outer boundary when the trapdoor was lowered. Based on the experimental results, a new composite arch model was proposed to calculate the soil pressure above a trapdoor, it can better describe the development of soil pressure in a trapdoor test.

Assessment of cohesive soil landslide driving forces exerted on piles considering soil arching effects

As known, the reinforcement effect of piles significantly relies on the precise assessment of cohesive soil landslide driving forces exerted on piles. However, the existing methods for estimating the cohesive soil landslide driving forces have scarcely considered the soil arching effects. Generally, this leads to prohibitively conservative approaches for pile stabilization. In this study, according to the Mohr Coulomb theory and the Ito plastic theory, a theoretical analysis method for quantitatively clarifying the distribution of cohesive soil landslide driving forces along piles is presented in detail, considering the vertical and horizontal soil arching effects between two adjacent piles in a pile row above the sliding surface. Centrifuge model test and full scale test of a pile-reinforced cohesive soil slope are introduced for verifying the proposed method, respectively. Compared with previous methods, the proposed method can prospectively produce results in better agreement with the test results. Ultimately, parametric analyses are conducted to investigate the effect of influencing parameters on the landslide driving forces, and the outcomes indicate a rational pile spacing and a small slope angle should be essentially considered for stabilizing a cohesive soil landslide effectively.

Soil-Pipeline interaction under localized soil Subsidence: Experimental Investigation

Localized soil subsidence can cause pipeline failures, yet relevant studies remain limited. This research uses 1 g scaling tests to explore granular soil behavior over a subsiding area with a crossing pipeline, employing Particle Image Velocimetry (PIV) and pressure sensors beneath trapdoors. Results reveal various failure mechanisms impacting load on pipelines, especially due to water-drop-shaped slip surfaces above the pipeline. The long side of the rectangular subsidence zone exhibited stronger load transfer compared to the short side. Neglecting the three-dimensional soil arching effect risks underestimating the pipeline load, particularly when the pipeline axis aligns with the long side of the subsidence. Greater distances between the subsidence zone and pipeline improve protection, though very close proximity can also be beneficial. The study suggests that inducing controlled soil failure above the pipeline may help reduce additional load, providing insights into mitigating pipeline damage from subsidence.

VOLATILITY SPILLOVER EFFECTS BETWEEN STOCK MARKETS DURING THE CRISIS PERIODS: DIAGONAL BEKK APPROACH

A rise in the yield of financial market assets could lead to variations in the returns of other assets over time due to arbitrage conditions. Consequently, this phenomenon may trigger spillover effects or cointegration among the volatilities of assets within financial markets. The aim of this study is to investigate spillover effects among American, European, Russian, and Turkish stock markets during the COVID-19 pandemic and the Russia-Ukraine war. Employing the diagonal BEKK-GARCH model from 2020 to 2023, the volatility transmissions within stock returns is examined. The results reveal significant GARCH effects alongside modest ARCH effects. Notably, during the COVID-19 period, the European market exerted the most significant influence on other markets, whereas during the war period, the US market dominated, and Turkish markets displaying the least impact for two periods. Furthermore, the findings indicate that the lagged cross-volatility persistence is lower during the Russia-Ukraine war period compared to the COVID-19 period.

Asymmetric mobilization of arching effect in granular materials: the role of fabric

We present an experimental and DEM investigation of the arching effect by focusing on the trapdoor test, with an emphasis on the effect of fabric orientation which is created by depositing particles at various directions. The results indicate that the arching effect is the weakest when the deposition plane is oriented at θ = 30°, which is manifested by the largest arching ratio for the trapdoor part and the most considerable particle movement. The arching effect mobilization is found to be asymmetric, apart from the cases θ = 0° & 90°. The arching ratio for the left bottom part is on average lower than that for the right bottom part, and the vertical particle displacement for the neighbouring zone at the left of trapdoor is comparably larger. The asymmetric mobilization of arching effect, as well as the occurrence of the weakest arching effect at θ = 30°, is also clarified.

Establishment of Pile-soil Interaction Model and Optimization Analysis of Distance Diameter Ratio

Abstract The anti-skid pile is s an effective method for slope treatment. Analyzing its stress law and designing reasonable schemes are urgent problems that must be solved to guide slope prevention and control, and in this paper, combined with the original anti-skid pile reinforcement scheme, 5 pile-soil interaction models with different distance diameter ratios D/d are established. The anti-skid pile and slope are discretized, and the slope displacement and safety factor, pile stress and deformation, and soil arching effect between piles are numerically analyzed so as to optimize the design parameters of spacing diameter ratio of anti-skid piles. The results show that (1) the distance diameter ratio of anti-skid piles negatively correlates with the safety factor. When D/d>2.8, the slope safety factor is 2.011>2.0. (2) The peak shear force and soil arching effect of anti-skid piles are positively and negatively correlated with the distance diameter ratio, respectively. The reaction force of the anti-skid pile suddenly changes at the soil-rock interface about 10 m away from the pile top, and local reinforcement should be carried out when the anti-skid pile is designed and optimized. (3) Based on the analog data of displacement and safety factor changes, pile body stress, and soil arch stress between piles, and considering economic factors, the optimal distance diameter ratio D/d is determined to be 2.8-3.0. Compared with other methods, the optimization method proposed in this paper has reasonable theory and sufficient data. The research results will provide theoretical reference and engineering technical guidance for similar slope reinforcement with anti-skid piles, and have specific application and promotion value.

Load transfer mechanism of floating pile-supported embankments under cyclic loading

Pile-supported embankments are one of the most commonly used techniques for ground improvement in soft soil areas. Existing studies have mainly focused on embankments supported by end-bearing piles under static loading, with limited research on floating pile-supported embankments under cyclic traffic loading. In this study, model tests for unreinforced floating, unreinforced end-bearing, geosynthetic reinforced floating, and geosynthetic reinforced end-bearing pile-supported embankments were conducted. Cyclic traffic loading was simulated using a three-stage semi-sinusoidal cyclic loading. Comparative analyses and discussions are performed under floating and end-bearing conditions to investigate the influence of floating piles on the soil arching evolution and membrane effect under cyclic loading. The results indicate that floating piles result in earlier stabilization of surface settlement. There is less arching and membrane effect induced by floating piles, and the arching does not continue to degrade under cyclic loading. Less membrane effect in floating pile-supported embankments results in less geosynthetic and pile strain. The degree of membrane effect in floating pile-supported embankment largely depends on the pile-end condition.

Correction: Mechanistic Study on the Fine-Scale Arch Effect of Moisture Content on the Dense Moulding of Mushroom Pomace Particles

Correction: Mechanistic Study on the Fine-Scale Arch Effect of Moisture Content on the Dense Moulding of Mushroom Pomace Particles

A frictional arch model for pile-cap-beam-supported embankment

The pile-cap-beam-supported (PCBS) system can strength the soil arching effect of embankment, increase the lateral stiffness, bending resistance and vertical bearing capacity of the rigid pile, however there is no frictional soil arch model of PCBS embankment. In this paper, first a frictional arch model for PCBS embankment modified from Russell’s frictional arching model was proposed. The proposed model in this paper considers the algorithm of lateral pressure coefficient k and a changing critical height of soil arch. In this new method, the influence of pile spacing, filling properties, height and pile spacing on critical height soil arch was comprehensively considered. Second, a series of numerical cases were performed to verify the effectiveness of the proposed model and study the arching effect of PCBS embankment. By comparing the vertical stress and settlement between the theoretical and simulation results, the rationality of the proposed method to estimate the stress and critical height of arch was validated. The effectiveness of the proposed method was further validated by comparing loading efficacy to a reported case. Last, the stress and deformation of PCBS and pile-cap-supported (PCS) embankment were analyzed and the superiority of PCBS system in improving the performance of embankment was observed finally.

An analytical solution to ground stresses induced by tunneling considering ground surface boundary conditions and gravity

Accurately predicting the stress distribution around the tunnel is crucial for designing safe and economical support systems. The stress distribution is closely related to the ground stress release induced by tunneling, as well as the initial gravity stress and boundary conditions. In this study, a two-dimensional analytical model considering the ground surface boundary conditions and gravity is presented to investigate the stress field around the tunnel. Then, a numerical model was developed to validate the proposed analytical model. Finally, parametric analyses were conducted, and the limitations of the load calculation method of the code for design of shield tunnel in China were discussed. The results indicate that: (a) Tunnel excavation induces stress redistribution in the soil, resulting in a soil arching effect around the tunnel. This arching effect causes nonlinear load changes around the tunnel. (b) The soil mass around the tunnel can be divided into undisturbed and disturbed zones. Above the tunnel, the disturbance range is C-2D(C and D represent the burial depth and the tunnel diameter), while below and on both sides of the tunnel, the disturbance ranges are 4D and 1.5D, respectively. (c) Once the stress release rate reaches 0.6, a combined arching effect zone, consisting of both major and minor principal stresses, is formed in the disturbance zone above and below the tunnel. (d) The load distribution pattern calculated by the code for design of shield tunnel in China is gourd-shaped, and this calculation method is insufficient for accurately evaluating the load around the tunnel. The research results can provide a reference for the design of the shield tunnel.

Influence of Excavation Radius on Behavior of Circular Foundation Pits Supported by Prefabricated Recyclable Structures: Full-Scale Experimental and Numerical Analysis

A foundation pit’s excavation area, which is determined by its radius in a circular foundation pit, exerts a considerable influence on the pit’s behavior. Using a full-scale experiment on a circular foundation pit retained by a prefabricated recyclable supporting structure (PRSS), this study develops a series of axisymmetric numerical models to systematically investigate the influence of excavation radius on the pit’s deformation, stress, and stability. Furthermore, simulation results from axisymmetric models are compared with those from plane strain models to illustrate the influence mechanism. The results show that at a given excavation depth, the deflection and bending moments of the supporting piles, the earth pressure on the non-excavation side, and ground surface settlement increase with the enlarged excavation radius, but the increase rate progressively decreases. However, the foundation pit’s safety factor decreases with an increasing excavation radius and gradually stabilizes. When the excavation radius exceeds 50 m, its influence on the foundation pit’s behavior significantly diminishes. The axisymmetric model results closely approximate those from the plane strain models, suggesting that the spatial arching effects of the circular foundation pit can be disregarded.